Fuse switch



1951 A. J. owuz 2,565,197

FUSE SWITCH Filed May 29, 1947 3 Sheets-Sheet l INVENTOR ZLMQW/M Aug. 21, 1951 J, BOWlE 2,565,197

FUSE SWITCH Filed May 29, 1947 3 Sheets-Sheet 2 IN V EN TOR Aug. 21, 1951 BOWIE 2,565,197

FUSE SWITCH Filed May 29, 1947 3 Sheets-Sheet 5 INVENTORT Patented Aug. 21, 1951 UNITED STATES PATENT OFFICE FUSE SWITCH Augustus Jesse Bowie, San Francisco, Calif.

Application May 29, 1947, Serial No. 751,256

9 Claims. 1

This invention covers improvements in automatic fuse switch cutouts, wherein after the fuse blows, the fuse tube disconnects itself from the cutout at one end.

Two types of automatic cutouts have'been'employed in the past; one v; th asealed tube wherein the blowing out of a sealing cap trips the fuse free from a top contact, and the other wherein the blowing of the fuse drops the tube down and releases a latch on the top contact clip.

My construction basically differs in that the fuse tube is made with a top ferrule latched thereto. After the fuse blows, this top ferrule is released and the fuse tube falls outof the ferrule and opens, the ferrule being retained in the top contact. These fuses will take what is commonly known as a universal fuse link. In order to operate under light loads, the top of the fuse tube must be sealed to the atmosphere after the fuse blows, and this I accomplish as shown. The tube parts also must be protected against high heat from heavy short circuits. To refuse, an inner clamp cap which secures the fuse link button is unscrewed, and the link inserted and fastened by this cap, the fuse pigtai-l passing through the tube. The outer top ferrule is then placed on the fuse tube and the fuse link is tightened under a screw in the lower end fuse contact or bottom ferrule. This positively locks the top ferrule. The fuse tube is inserted in a lower trunnion contact while it hangs downward. The upper clip I make preferably with a pivoted lever with spring contacts which engage the top ferrule. This lever is under springtension, causing the ferrule to move upward when released. To replace the fuse tube, this lever -is pulled down and latched, but when the top ferrule is inserted in the spring contacts it unlatches the latch and places the fuse tube under tension. When the fuse blows, the fuse tube latches securing the top ferrule, are released, and the top ferrule is pulled off, and the fuse tube swings down, thus opening the circuit.

Fig. 1 shows a side elevation of the fuse switch.

Fig. 2 shows a similar elevation after the fuse has blown and the tube has swung to the open position.

Fig. 3 shows a longitudinal section of the fuse tube with top ferrule latched, and the fuse in tension. 7

Fig. 4 shows a similar top elevation in section with the fuse blown and latches released.

Fig. 5 is a cross-section of Fig. 3 .on line 55.

Fig. 6 is a plan of the top fuse contact.

Fig. 7 is a section thereof on line 11 of Fig. 6.

Fig. 8 is a section on line .88 of Fig. 1.

Fig. 9 is a section on line 9-9 of Fig.8.

In Fig. 1, l is a fuse tube, preferably'of horn fiber lined Bakelite; 2 is a lower metal endor ferrule secured on the bottom end of the tube, with nut 37 for attachment of fuse pigtail 38;

35 is a bottom contact clip, in which fuse end 2 trunnions.

The cutout consists of an insulator 31, with clamp band 32 at the center for attaching to a support bracket 33 adapted for crossarm or other mounting. At each end of insulator 3| are bands .34 and 34A, for supporting the two terminal clips of the cutout, namely, 35 and 9, with its-springs 26 and 21.

In Figs. 3 and 4, 3 is a top cap screwed to fuse tube l; I is a movable piston, to which the top button and extension 9 of the universal link is clamped by cap nut 8, the link including the fuse 36 itself and lead 38; I9 is a spring within piston l, which drives it upward against stop nut 6'; 5, 5 are latches mounted on pins 18, I 8, trunnioned in cap 3; 4 is a top ferrule sliding freely on cap 3, provided with an inner groove for engaging latches 5, 5.

fuse itself only carries the smaller tension imposed by the spring lil. When the fuse blows, the tension on ferrule 4 causes it to disengage from latches 5, 5, after piston 1 has moved upward against stop nut 6. When this takes place, ferrule 4 is pulled free from cap 3, leavin the fuse tube free to swivel and drop open in clip 35. I l is a pigtail soldered to terminal end l2. The other end of the flexible pigtail solders in screw closure 6, which is secured against turning by screw l-B, fastened also to cap 3.

I3 is a spring contact clip, mounted in ferrule 4, and contacts socket 3. 1'! is a lock rod mounted on piston I, which rides in a hole on nut 6. This holds piston i from rotation when screwing or unscrewing cap nut 8.

Sleeves i l, I5 fit loosely inside cap 3 and piston l, the function thereof being to make a labyrinth passage and to protect spring to from hot gases when the fuse blows. The fit of cap 3 and lower part of piston 1 closes the top fuse end against leakage from tube l to the atmosphere when the fuse blows. The upper terminal base l9 supports swivel lever 20 which is pushed by compression spring 23 through spring end 22, secured to lever 20 by pin 30.

Fig. 7 shows a side elevation and Fig. ,6 a top plan of the top clip contact with the fuse in position. The lower end of the fuse tube is open to the atmosphere through the bottom ferrule, so that pressure generated by blowing the fuse link will expel'the lead 38 from the fuse tube .and break the are even before the fuse tube is fully released from the ferrule 4. The tension of spring 23 through pin 30 in spring end '22 tends to pull up ferrule 4. When the fuse blows, ferrule 4 moves upward, with contact bars 26 and 21, which ontact therewith. Lever 29 i mounted on pin 28, set in base [9. Latch 2| is mounted on pin 29, set in base l9, and has its left end pushed down by spring 24. After the fuse has blown, ferrule 4 is removed from springs 26 and 21 by a fuse stick. A down pull on spring 26 causes latch 2! to engage lever 20 and hold it in position. The insertion of ferrule 4 between springs 26 and 21 results in this ferrule striking latch 2| and freeing it from lever 29, the up pressure of springs 26 and 21 being taken on ferrule 4.

The current path is from clip 35 through fuse to piston 1, capnut 8, lug l2, igtail H, closure 6, cap 3, clip I3, ferrule 4, springs 25 and 21 and flexible contact 25 attached to lever 20.

This invention particularly covers a fuse switch which disconnects the tube when the fuse blows. An important feature covers a fuse tube assembly, preferably under tension, contact clips, and a fuse element within the tube subjected to tension, and means when the fuse element blows for releasing tension therein to allow the fuse tube assembly to part and the fuse tube to open. It is preferable to protect tension on the fuse tube from the fuse element, and hence an interlocking arrangement is desirable. There should also be a spring arrangement for fuse tube tension to Withdraw the ferrule of the fuse tube assembly from the fuse tube.

What I claim is:

1. In a fuse switch, an insulating support, a pair of contacts attached thereto, a fuse tube assembly comprising an insulating tube with a pair of ferrules mounted on opposing ends for bridging said contacts one of said ferrules being movably mounted on said fuse tube a cap for permanently closing said fuse tube within said moveable ferrule, a fuse element within said fuse tube, means for securing said movable ferrule on said fuse tube and for releasing it when said fuse blows, and means for causing said fuse tube to move apart from said movable ferrule after said fuse blows.

2. In a fuse switch, an insulating support, a pair of contacts attached thereto, a fuse tube assembly comprising an insulating fuse tube with a pair of ferrules mounted on opposing ends for bridging said contacts one of said ferrules being movably mounted on said fuse tube, a permanent closure for said fuse tube within said moveable ferrule, a fuse element within said fuse tube,

4 end of said tube and secured thereto, an outer ferrule fitted slideably over said cap, latching means for holding said ferrule and cap in engagement, a ferrule mounted on the other end of said tube, a fuse link connecting said cap and said second ferrule, said link including a fusible portion, and means operative by tension on said means connected to said fuse element and retained by tension thereon for securing said movable ferrule on said fuse tube, and for releasing it when said fuse blows, and means for causing said fuse tube to move apart from said movable ferrule after said fuse blows.

3. In a fuse switch, an insulating support, a pair of contacts attached thereto, a fuse tube assembly comprising an insulating tube with a pair of ferrules mounted on opposing ends for bridging said contacts one of said ferrules being movably mounted on said fuse tube, a permanent closure for said fuse tube within said moveable ferrule means for moving said movable ferrule by tension applied thereto, a fuse element within said fuse tube, means for securing said movable ferrule on said fuse tube and for releasing it when said fuse blows and means for causin said fuse tube to move apart from said movable ferrule after said fuse blows.

4. A fuse cut-out comprising an insulating fuse tube, a conducting cap fitted over and closing one link for maintaining said latching means in engagement, whereby fusion of said link releases said ferrule from said cap.

5. A fuse cut-out in accordance with claim 4 including a slideable piston within said cap, a shoulder on said piston bearing against said latching means to hold'the same in engagement with said first mentioned ferrule and a spring tending to force said shoulder out of contact with said latching means, said spring being stressed by said link to maintain such contact until said link is fused.

6. A fuse cut-out in accordance with claim 4 including means on said first mentioned ferrule for engaging a switch mechanism to retain said ferrule therein when disengaged by said latching means, and means on said second ferrule moveably engageable with said switch mechanism.

7. A fuse cut-out in accordance with claim 4 including a plurality of baffles within said cap forming a labyrinth restraining the emmission of gas from within said cap.

8. A fuse cut-out in accordance with claim 4 including a slideable hollow piston within said cap having a shoulder thereon bearing against said latching means to hold the same in engagement with said first mentioned ferrule when said piston is retracted, a spring within said piston tending to force said shoulder out of contact with said latching means, said spring being stressed by said link to maintain such contact, and tubular baffles within and without said spring and secured respectively to said piston and said cap to form a labyrinth restraining emission of gas from said cap and protecting said spring from such gases.

9. A fuse switch comprising an insulating support, a pair of contact members secured to said support and a fuse tube assembly pivotally mounted to one of said contacts and engageable with the other of said contacts, said fuse tube assembly comprising an insulating tube, a fuse link within said tube and a conducting ferrule secured to the end of said tube and releasable therefrom upon blowing of said fuse link; said second mentioned contact on said support comprising an arm mounted to swing in the plane of said fuse tube, means on said arm for engaging said ferrule, and a spring acting on said arm to tension said fuse assembly when so engaged, a latch for holding said arm in position to receive said assembly against the action of said spring, and means actuated by the engagement of said ferrule for releasing said latch.

AUGUSTUS JESSE BOWIE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,940,203 Bowie Dec. 19, 1933 2,115,592 Smith Apr. 26, 1938 2,172,143 Lemmon Sept. 5, 1939 2,231,599 Smith, Jr. Feb. 11, 1941 2,310,069 Fahnoe Feb. 2, 1943 

